On 2018, July 12th the famous Gate of Glory in Santiago de Compostela has been re-opened. This extraordinary document of art and thinking still leaves us astonished and admired. The many colours of the original gate have been partially restored, giving a new look,a new surprising light to the monument.

At the same time NEW researches have revealed that a polyphonic experience lies behind the depictions of musical instruments in the hands of the 24 Elders of the Apocalypse, all around the arch.

All instruments are depicted in couples (2 harps, 2 lauds ...etc.) suggesting they can be played in duet. The so-called Organistrum, at the top of the arch, played by two musicians, shows a chromatic scale, thus indicating a possible extraordinary evolution in musical thinking at Santiago de Compostela during the 12th century.

Then, two-voices compositions in Codex calixtinus witness the developement of Polyphony at Santiago in the same age.

In our studies we have clearly demonstrated that Portico de la Gloria top instrument is a SPECIAL ONE, different from any other "two men lyre" known. In fact, its chromatic scale, quite useless for sacred music at that age, has suggested us the creation of a POLYPHONIC KEYBOARD that serves perfectly 12th century new polyphonic repertory. If the first "two men lyre" with its diatonic scale could help may be accompanying simple polyphonies such as those discribed by "Musica enchiriadis" and "Micrologus", SANTIAGO's INSTRUMENT is the improvement of it, the herald of a new musical world.

This shed a new light over the whole Portico della Gloria music instruments setting: the couples are actually showing a polyphonic idea, not following only a sort of scenical arrangement.

Such as nowadys "chromatic restoration" of the gate: everything there shines in a better light !